1. Field of the Invention
The present invention relates to the pacing of a heart, and more particularly, pertains to detection of a pacing artifact in an ECG signal.
2. Description of the Prior Art
Previous prior art patents rely solely on analog circuitry to filter out all but the high frequency edges of pacing pulses. There are many variations on the types of filters such as differentiator, or high pass filter, band pass filter, or combinations thereof; filter parameters such as cutoff frequencies, gains, etc.; and, the circuit implementations used for the filters.
U.S. Pat. No. 5,010,888 issued to Jadvar et al. describes variations on analog circuitry to detect and remove pacemaker pulses from an ECG signal (as opposed to highlighting them). Removal is desirable when the pacing pulses are large, and cause the ECG to be difficult to interpret, either from an ECG recorder or by a computerized ECG analysis system. U.S. Pat. No. 4,664,116 issued to Shaya et al. describes an analog circuit to detect pacemaker pulses, utilizing an adjustable detection threshold. U.S. Pat. No. 5,022,404 issued to Hafner describes analog circuitry to detect pacemaker pulses from an ECG signal(s), with the additional purpose of storing and/or transmitting the signal(s) to another location. U.S. Pat. No. 5,127,401 issued to Grevious describes analog circuitry to detect pacemaker pulses, utilizing multiple simultaneous lead vectors to improve the signal to noise ratio. U.S. Pat. No. 5,029,082 issued to Shen et al. describes a system that utilizes digital signal processing techniques and integrated circuits to do a variety of processing on various bioelectric signals such as ECG, VGG, EEG, etc.
Previous prior art devices are plagued by the following problems; noise from patient movements, bad lead connections, interference from pacemaker telemetry systems or other electrical equipment nearby. The problems could be erroneously detected as pacing pulses. In designing to eliminate the noise problem sufficiently, the sensitivity of previous inventions has been compromised. This becomes more of a problem as the trend toward using lower pacing energies whenever possible continues. Previous inventions can not automatically adapt to a wide variety of signal conditions. In addition, pacemakers utilizing minute ventilation (MV) sensors, which deliver a series of current pulses at a high frequency, pose a problem to previous inventions. These current pulses, used to measure the impedance of the heart, are erroneously detected as pacing pulses.
The present invention overcomes the disadvantages of the prior art by providing a heart pacing pulse detection system such as for a pacemaker programmer.